Bumping Smut from the World Wheat Trade Scene

By Carol Flaherty

02/23/00 BOZEMAN, Mont. - Face it, smut has a bad "rep." Its definition can range from a smudge to an obscenity, but none of the definitions are good.

When it comes to the plant disease that is caused by TCK smut, the reputation has cost northwestern United States winter wheat growers their share of the Chinese wheat trade since 1972.

Reopening that trade required both political and scientific agreements. Though international trade agreements have gotten center stage with the resumption of World Trade Organization negotiations, resolving whether or not smut in Pacific Northwest wheat could damage China's winter wheat crop was a necessary precursor.

The Chinese weren't alone in their concern. Brazil and Chile also banned wheat shipped from the U.S. Pacific Northwest because of the potential of smut contamination. Some people thought the bans were purely political, but not Don Mathre.

"I think China truly believed TCK smut was a threat to its wheat production, and thought it could cause losses like the potato blight once did in Ireland," says Mathre, a plant pathologist and emeritus professor of Montana State University's Plant Sciences Department.

About 1980 U.S. Wheat Associates invited a scientist from the People's Republic of China to work at Oregon State University and cooperate with scientists at other state universities. China sent Dr. Zhihong Zhang. He worked in the United States for three years cooperating with Mathre and Bill Grey at Montana State University, Jim Hoffmann of USDA at Utah State University, Bob Powelson at Oregon State University and J. A. Fernandez at the University of Wyoming. The USDA's Blair Goates at the University of Idaho later confirmed their work with additional research in the 1990s. In total, this risk assessment work led to convincing the Chinese that TCK smut did not represent a threat to its winter wheat regions.

Getting to that point was a not just a multi-state effort, but also relied on the cooperation of grain marketing companies, the Federal Grain Inspection Service.

The initial step was to determine how much grain showed evidence of TCK smut.

The first findings were not reassuring: about 50 percent of the winter wheat leaving Pacific Northwest ports tested positive for smut, says Bill Grey, another MSU plant scientist.

Then the question became, "How many spores of "Tilletia controversa Kuhn" smut did it take to cause the disease known as dwarf bunt?"

In hindsight, the scientists now know that the ability to identify TCK smut spores far surpassed the fungus' ability to cause trouble, says Grey, but it took reams of data to prove that.

TCK spores.

"China was concerned that grain that contained any spores would cause contamination," says Grey. "Theoretically, they were right, one spore could do it. But in application, it ended up that over 60,000 spores of TCK are necessary to infest a field, and then only if that field had 60 days of snow cover a year and met other climatic conditions."

The USDA formed a risk assessment committee to study this and other aspects of TCK smut's potential to damage Chinese wheat growing.

Part of the USDA Risk Assessment report presented to the Chinese included an analysis of the primary Chinese winter wheat growing region climates. Taking that information, the number of spores necessary and the number of shipments involved, the risk assessment showed a less than 1 in 100,000 possibility of TCK establishing in China's winter wheat growing region. When multiple factors were included in the analysis, the odds of TCK establishing in China's winter wheat regions was about two in a million.

It turned out that almost all of the potential for TCK establishment in China was in the spring wheat region, and the disease is only a problem on winter wheat.

Technically, smut as an obstacle to trade was solved in April 1999, when the People's Republic of Chinese signed an agreement acknowledging that TCK smut did not threaten their wheat crops.

Before any orders for wheat might occur, however, the NATO/U.S. bombing of the Chinese Embassy in Belgrade in early May 1999 put the issue on hold.

Since then, no wheat has been bought by the Chinese through the Northwest ports of Seattle or Portland since then, says Cheryl Tuck of the Montana Wheat and Barley Committee. China's announcement in Great Falls Feb. 23, 2000 that they would buy a load of wheat to test for quality is the next step in the process of fully implementing wheat trade from Pacific Northwest ports.

How much such sales might influence the price of wheat or the quantity of U.S. wheat exports is unknown.

Linda Young, an MSU economist with the Trade Research Center, pointed out that the quantity of wheat China imports fluctuates.

"Prices of wheat in Montana won't skyrocket," says Young. "What really matters in terms of prices is how much China imports." She said that in 1994-95, China purchased 10 million metric tons of wheat to make up a domestic shortfall, but imports can be as low as 1.5 million metric tons in other years.

"The bottom line is that lifting the restrictions is good, and it is better for Montana than anywhere else, but it won't make big bucks for Montana producers. China has a reputation for being very careful about how much it pays for wheat."

Send questions or comments to Don Mathre, Bill Grey and Carol Flaherty, MSU Communications Services, Bozeman, MT 59717: carolf@montana.edu.

You are the 9100th person to access this page.